Human-caused warming to surpass Paris Agreement limit by 2037, analysis finds

Human-caused global warming is set to surpass 2.7° Fahrenheit (1.5° Celsius) by the year 2037, overshooting an international goal beyond which severe climate disruptions may become the norm, according to a new analysis from 50 climate scientists.

“This is unprecedented in anything we have seen historically,” said Piers Forster, a professor at the University of Leeds and an author on the paper. Forster has also authored multiple climate reports with the Intergovernmental Panel on Climate Change (IPCC), widely regarded as the international authority on climate science.

The 2016 Paris Agreement, which has been signed by nearly every country in the world, set an international goal to halt warming at 2.7° Fahrenheit. Beyond this point, scientists believe the effects of climate change will escalate, with widespread die-offs of coral reefs, common extreme heat waves, and destructive flooding of coastal cities. The study found that the global increase in temperatures has reached 2.05° Fahrenheit over the past decade.

The planet is also warming increasingly faster, with temperatures rising by an unprecedented 0.36° Fahrenheit since 2013, according to the new paper, published today in the journal Earth Systems Science Data.

“This is the critical decade for climate change,” said Forster in a statement. “Decisions made now will have an impact on how much temperatures will rise and the degree and severity of impacts we will see as a result.”

The scientists’ analysis also gives an update on humanity’s remaining carbon budget — the amount of greenhouse gas emissions humans can still emit to stay under the 2.7° Fahrenheit limit. According to the paper, the remaining carbon budget has halved since the IPCC calculated it in 2020. Now, humans have just 250 gigatonnes of carbon dioxide left to emit, compared with the 500 gigatonnes available just three years ago — meaning ‘business as usual’ activities are expected to exhaust the carbon budget by 2029.

“If we don’t want to see the [IPCC] goal disappearing in our rearview mirror, the world must work much harder and urgently at bringing emissions down,” Forster said in a statement.

Greenhouse gas emissions reached an all-time high over the last decade. In 2021, emissions rose to over 54 gigatonnes of carbon dioxide. The remaining carbon budget is “very small” in the context of humanity’s yearly emissions, said Joeri Rogelj, a professor of climate science at Imperial College London and an author on the paper. Rogelj is also an author of IPCC reports.

Greenhouse gas emissions are now on par with the emissions in 2019, just before the coronavirus pandemic caused worldwide lockdowns, he said. 

As the climate changes more quickly, scientists need to keep up with their analyses, too, said Forster. While the IPCC reports valuable and in-depth climate information, it only releases its major assessments every five to ten years. Today’s new research is an attempt to fill in the gaps left by the IPCC’s assessment cycle. 

The new paper is part of an initiative launched today led by Forster and the University of Leeds, called the Indicators of Global Climate Change Project, which aims to update climate analyses each year to keep people informed about the climate crisis.